Zero grind question

[Ccc]

Hey everyone,

Sorry if this has been asked before, I did a search and couldn't find anything relevant. Hopefully I am not just really bad at searching...

I have a XM-18 in CPM20CV that I would like to get reground thinner. I really like the zero grinds I have seen and am considering getting one done for my knife.

Does anyone have any experience (good or bad) with zero grind edges? Stability, extra prone to chipping or rolling, etc?

I will use this knife mostly for food, packages, and fire prep while camping, but sometimes for yard work or breaking down boxes and crates and cables.

Any information anyone has about different steels and uses would be appreciated,

Thanks!

Chris

 

[collim1]

It depends on the steel.

I use Moras a lot. They cut rope, carve wood, and dress deer/fish frequently. Wood, flesh, rope etc...no problems. Learned the hard way not to split a deer pelvis with one, it will chip the edge.

Scandi edges are great for soft woods and flesh. The kind of stuff you do in the woods. Other stuff not so much in my experience.

My only other scandi edge is a CS Finn Wolff. I have not thoroughly tested mine, but it appears its a flop. Lots of reports of the edges chipping and rolling through very modest material. It may just need a few sharpenings to get the edge set, just have to wait and see.

Most scandi ground knives are designed to be given a scandi edge. The steel and heat treat is intended for that purpose. I would be weary of taking a knife and converting it into a scandi. Could be fine, could be useless afterwards.

 

[matus]

May I ask what do you mean with zero grind? Do you mean that there is basically no edge bevel (or quasi zero thickness of the blade behind the edge)? First of all - in really you will rarely use zero bevel. Even on kitchen knives that are exceptionally thin behind the edge one usually applies a micro-bevel (barely visible with naked eye) to increase the edge strength.

Now whether you should or should not do that depends on many factors - steel & HT is an important one, but as well as the angle of the main bevel. The already mentioned scandi grinds do not really need an edge bevel, as the main bevel has a very large angle. But with a utility blade with much smaller edge bevel you may quickly find the edge not stable enough (roll, chip, edge holding) for some tasks.

The best way is to try - have your knife reground the way you like. If you the find that the edge stabiliy or chipping is a problem, you can apply an edge bevel with little effort and experiment untill you have edge that you like.

 

[pinnah]

Hey everyone,

Sorry if this has been asked before, I did a search and couldn't find anything relevant. Hopefully I am not just really bad at searching...

I have a XM-18 in CPM20CV that I would like to get reground thinner. I really like the zero grinds I have seen and am considering getting one done for my knife.

Does anyone have any experience (good or bad) with zero grind edges? Stability, extra prone to chipping or rolling, etc?

I will use this knife mostly for food, packages, and fire prep while camping, but sometimes for yard work or breaking down boxes and crates and cables.

Any information anyone has about different steels and uses would be appreciated,

Thanks!

Chris

Chris,

I would recommend getting a guided rod system like a Lansky or DMT Aligner and setting a back bevel at 15 or 17 degrees per side and a micro-bevel at 20 degrees per side.

We need to be clear on definitions. Pictures will help.

These pictures can be used to describe the entire blade grind, or the edge geometry near the cutting apex. In terms of the overall blade grind, your knife is currently like #3. There is a flat section near the spine and the primary grind to the edge is flat on both sides.

But, we need to talk about what is going near your edge bevel. Currently, at the edge, your edge geometry looks something like #3 again, only instead of it being flat, the primary grind comes down to the edge at a shallow angle and then you have a crisp 'V' cutting edge at a steeper angle. Just making up the numbers here but your primary blade grind might be at 9 degrees per side and your cutting edge might be at 20 degrees per side. With a traditional 'V' edge geometry, there is a very clear and distinct transition or "shoulder" where the primary grind stops and the cutting 'V' edge begins.

As I understand how the term gets used, a so-called 0 grind is one that doesn't have a distinct shoulder near the cutting edge.

One way to do this are to use a true, full flat grind that extends all the way to the cutting apex. This would look like #2 and it would take significant amount of stock removal from your current blade and it would also leave you with a very, very thin blade near the edge. So thin that you should be concerned with edge stability. This sort of grind might make sense for high end kitchen knives but I think most people consider it too frail for EDC and camping use, as you describe.

Another way to do this is use a so-called Scandi grind. This would look like #3 in terms of the primary grind. The difference from this and what is on your knife is that you would need to "sharpen" the entire primary grind. I don't think your Hinderer was designed for this. The Mora Companion has an edge angle of around 13 degrees per side and this leaves a much taller flat section and a much shorter primary grind that what is on your Hinderer. I would think that given how shallow your primary grind is, you would end up with a super thin and fragile edge.

Another and more common approach is to put a "convex" edge on your blade. Near the cutting apex, it would look more like #6 with no pronounced or visible transition from the primary bevel to the cutting apex. People who talk about sharpening using a mouse pad are going for this. Most people who use convex edges report better edge stability and better slicing. I agree with this.

I'm going to recommend something different though. I would recommend you get a guided rod sharpening system with diamond stones. I'm referring here to a system like the Lansky or DMT aligner. I would then recommend that you put on an aggressive back bevel to thin the edge. The result near the cutting edge will end up looking like #5 above. So, if your primary grind is 9dps and your cutting apex angle is 20dps, you could set your back bevel to something like 17dps.

I found that using an aggressive back bevel gives nearly all of the advantages of a true convex edge but offers the advantage of being easy to achieve and maintain on a guided rod system.

 

[onojoe]

Chris,

I would recommend getting a guided rod system like a Lansky or DMT Aligner and setting a back bevel at 15 or 17 degrees per side and a micro-bevel at 20 degrees per side.

We need to be clear on definitions. Pictures will help.

These pictures can be used to describe the entire blade grind, or the edge geometry near the cutting apex. In terms of the overall blade grind, your knife is currently like #3. There is a flat section near the spine and the primary grind to the edge is flat on both sides.

But, we need to talk about what is going near your edge bevel. Currently, at the edge, your edge geometry looks something like #3 again, only instead of it being flat, the primary grind comes down to the edge at a shallow angle and then you have a crisp 'V' cutting edge at a steeper angle. Just making up the numbers here but your primary blade grind might be at 9 degrees per side and your cutting edge might be at 20 degrees per side. With a traditional 'V' edge geometry, there is a very clear and distinct transition or "shoulder" where the primary grind stops and the cutting 'V' edge begins.

As I understand how the term gets used, a so-called 0 grind is one that doesn't have a distinct shoulder near the cutting edge.

One way to do this are to use a true, full flat grind that extends all the way to the cutting apex. This would look like #2 and it would take significant amount of stock removal from your current blade and it would also leave you with a very, very thin blade near the edge. So thin that you should be concerned with edge stability. This sort of grind might make sense for high end kitchen knives but I think most people consider it too frail for EDC and camping use, as you describe.

Another way to do this is use a so-called Scandi grind. This would look like #3 in terms of the primary grind. The difference from this and what is on your knife is that you would need to "sharpen" the entire primary grind. I don't think your Hinderer was designed for this. The Mora Companion has an edge angle of around 13 degrees per side and this leaves a much taller flat section and a much shorter primary grind that what is on your Hinderer. I would think that given how shallow your primary grind is, you would end up with a super thin and fragile edge.

Another and more common approach is to put a "convex" edge on your blade. Near the cutting apex, it would look more like #6 with no pronounced or visible transition from the primary bevel to the cutting apex. People who talk about sharpening using a mouse pad are going for this. Most people who use convex edges report better edge stability and better slicing. I agree with this.

I'm going to recommend something different though. I would recommend you get a guided rod sharpening system with diamond stones. I'm referring here to a system like the Lansky or DMT aligner. I would then recommend that you put on an aggressive back bevel to thin the edge. The result near the cutting edge will end up looking like #5 above. So, if your primary grind is 9dps and your cutting apex angle is 20dps, you could set your back bevel to something like 17dps.

I found that using an aggressive back bevel gives nearly all of the advantages of a true convex edge but offers the advantage of being easy to achieve and maintain on a guided rod system.

That's some good sh!t right there

 

[Ccc]

Thanks for the advice, everyone. I love the look of having one grind all the way to the edge, but it's clear that is not great for what I want to use this knife for. I will just have to get another knife as a dedicated slicer

 

[matus]

I agree - getting a dedicated slices is the best way to go. In particular as (most probably) the HT & geometry on the knife was optimized for certain use. Applying too strong change to blade geometry may result in disappointing performance. And anyhow - getting another knife is always a solution

 

[Ajack60]

Thanks for the advice, everyone. I love the look of having one grind all the way to the edge, but it's clear that is not great for what I want to use this knife for. I will just have to get another knife as a dedicated slicer

Go look at Big Chris regrind thread. I had a spanto that he re ground to a slicer and it's absolutely a true slicer. He has pics posted, that may be what you're looking for. From what Chris told me, Hinderer has a higher RC and mine is S35VN.

 

[pinnah]

I agree with Ajack, don't give up yet.

If you want better slicing and an edge stable enough for EDC and camping, you can get both. For this, I would recommend:

a) Avoid the term "0-grind" as it is too broad and too easy to mis-interpret. Instead, if you're going to send the knife out, be more specific about what you want from the knife in terms of performance and then discuss what you want or expect to be done in different parts of the blade.

b) Focus on flattening the transition from the flat that comes from the spine to the primary grind of the blade. To get the idea, lay the blade flat on a cutting board and rock it back and forth so either the spine or edge touch the board. The sharp pivot point is what you're looking to eliminate. It's that sharp, well defined shoulder that hangs up in potatoes and apples and the like.

Here is a Case hollow-ground fixed blade that is part way through this sort of treatment.

https://www.flickr.com/photos/pinnah/sets/72157628500397713/

You can see how the transition line of the shoulder is moving down the blade. I've since brought it down more consistently and this transformed the slicing ability.

c) Treat the edge seperately to maintain edge stabillity. Options include leaving it as a pure 'V' edge, a convex edge or a compound edge. I use a Lansky to establish my edges as a compound edge (very consistent) and then maintain my edges free hand which allows them to naturally move to a convex edge. I find this gives me better slicing than a pure 'V' and good edge stability.

Hope this helps

 

[dalefuller]

Pinnah's advice is right on target, esp. #9b. I have a couple of Emersons that I had ground straight from the bottom of the flat at the top of the blade all the way to the edge. Not a zero grind like pic #2, but more like pic #3. They were also thinned a bit with the regrind. They are outstanding slicers. They cut with almost no pressure required. BUT... I'm very careful using them. They are slicers. I don't use them where I might need lateral pressure. They're great for food, cardboard, zip ties, tape, even light plant stem trimming... anything I can slice straight through keeping all the pressure on the cutting edge of the blade.

I don't use them for heavier outdoor stuff and I don't carry them everyday because I never know what I'll need to do with a knife on a day-to-day basis. I prefer convexed or flat ground blades for general daily use. You can still have a blade thinned a bit if the stock is too thick without making it a zero grind, and you can eliminate the strong shoulder (pivot point) that pinnah's talking about and get a noticeable performance increase.

 

[Lycosa]

yep!^
Phill Hartsfield would ask his customer what the knife would be used for and put on the appropriate edge geometry.

 

[pinnah]

PI have a couple of Emersons that I had ground straight from the bottom of the flat at the top of the blade all the way to the edge. Not a zero grind like pic #2, but more like pic #3.

Yes.

And if the OP only has his ground flat from the spine to about 1/2 way down the blade, he can have improved slicing while still keeping the edge stability that the knife currently has. Not perfect slicing, but improved.

That's how I would describe my Case Sodbuster that I'm carrying today. Flat blade grind but still traditional and not overly thinned convexed cutting edge. This slices well with food but so long as I don't take the cutting edge too thin, will still hold up to working with wood reasonably well.